Storage area networks (SANs) are increasingly used, particularly in business enterprises, to enable network servers to share storage arrays and/or storage devices. It is important for those managing such networks to be able to keep track of and to change storage configurations quickly, easily and flexibly. Accordingly, SAN management software commonly provides for topology mapping, wherein all devices and connections of the network are sought to be discovered and displayed. Typically, host agents discover devices physically or logically connected thereto, and report these discoveries to a management server. The management server processes this information from the hosts to identify associations between various devices in the network, and then produces a topology map.
In some cases, the SAN management software is unable to detect associations between certain devices in the network. Take, for example, the simplified SAN shown in FIG. 1, which includes a tape library having multiple internal tape drives and a robot/controller. As shown in FIG. 1, tape drive 1 and the robot/controller are attached to bridge 1, while tape drives 2, 3 are attached to bridge 2. A host connected to the SAN and using the tape library detects logical unit numbers (LUNs) for each of the tape drives, as well as one for the robot/controller. The host uses these LUNs when communicating with the tape library to request a tape (from the robot/controller) or to write/read data to/from a tape drive.
Unlike the robot/controller, however, the tape drives cannot identify the tape library to which they belong. When SAN management software communicates with the tape drives, the drives can identify themselves, and can even indicate that they belong to a tape library, but they cannot identify the specific tape library to which they belong. Thus, the SAN management software cannot determine that the tape drives connected to bridge 2 belong to the same tape library as tape drive 1 and the robot/controller. Therefore, the topology map produced by the SAN management software may appear like that shown in FIG. 2. Because the topology map shown in FIG. 2 only depicts the tape library generally, and not the individual tape drives and the robot/controller associated with the tape library, it appears from the map that no devices are attached to bridge 2. As recognized by the inventors hereof, this may be confusing to and mislead individuals interpreting the topology map because, in this example, there are actually two tape drives attached to bridge 2. The inventors have also recognized that, even if the management software was configured to produce a topology map that depicts the individual tape drives shown in FIG. 1, the map would still fail to illustrate that tape drives 2, 3 are associated with the same tape library as tape drive 1 and the robot/controller. Instead, such a map would depict tape drives 2, 3 as stand-alone tape drives connected to bridge 2 (or to bridge 1, if the SAN of FIG. 1 was so configured), which could likewise confuse and/or mislead individuals reading the map.